The objectives of this program are to develop and otherwise obtain, characterize, expand, bank and distribute cell lines of use for studies on cancer of the large bowel. Work with tissues of human and laboratory animal origins was proposed. Twenty-five cell lines from human colorectal tumors, two skin fibroblast strains from individuals predisposed to adenomatosis of the colon, one cell line from a chemically induced tumor of the mouse and three normal mouse intestinal epithelial lines have been received. In addition, a number of fibroblast-like strains have been developed from colon tissue of presumptive normal humans of differing ages. The species of each line received has been verified by isoenzymology and each has been tested for the presence of bacterial, mycoplasmal, fungal, viral and protozoan contaminants. Lines shown to be free of such adventitious agents have been expanded to produce larger stocks. Progeny from these have or are being characterized further with regard to karyology, isoenzymology, tumorigenicity, growth properties, antigenic markers, and ultrastructure. Eleven such seed-distribution stocks are currently available. These include ATCC.CCL 218 (WiDr), CCL 220 (COLO 320DM), CCL 220.1 (COLO 320HSR), CCL 222 (COLO 205), CCL 224 (COLO 201), CCL 228 (SW-480), CRL 1459 (CCD-18Co), CRL 1539 (CCD-33Co), CRL 1541 (CCD-112Co), CRL 1532 (182PF) and CRL 1533 (166ME). All features of each line are included in the new ATCC Catalogue of Strains (January, 1981). An additional 6 lines are now available for release pending committee certification.